A New Model for Fnvelope Tracking Power Amplifier Modeling and Digital Predistortion

Envelope Tracking (ET) is regarded as a potent technology to enhance the efficiency of RF Power Amplifiers (PA). On the other hand, because of the high PAPR and large bandwidth in modern communication systems like LTE/LTEA, ET also introduces a significant memory effect distortion. This paper provides a new behavioral model with improved performance in modeling and linearization technique for Envelope Tracking Power Amplifier (ETPA). The proposed model takes the traditional Memory Polynomial (MP) model of fixed supply voltage PAs as a prototype, and modulates the coefficients along with the envelope signal which controls the supply voltage of ETPA. The proposed model showed a high accuracy performance at -43.5dB Normalized Mean Squared Error (NMSE) and 52.7dB Adjacent Channel Error Power Ratio (ACEPR) as a PA behavioral model. Also the proposed new model can be adopted in digital predistortion technique of ETPA system, which simulated to improve 5.3dB in NMSE and 5.2dB in Adjacent Channel Power Ratio (ACPR) against MP modeled predistorter.